<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <button>按钮</button>
    <script>
        let btn = document.querySelector('button');

        btn.onclick = function() {
            // confirm('今天吃了吗？')
            let bool = confirm('今天吃了吗？');

            // console.log(bool);

            if(bool){
                let a = confirm('你确定吗？');
                if(a){
                    let b = confirm("真的确定吗？");
                    console.log("吃了");
                }else{
                    console.log("没吃");
                }
            }else{
                console.log("没吃");
            }

        }
    </script>
</body>
</html>